Instrument fob facilitating- the facing of millstones



B. D. SANDERS.

Testingthe Trueness of Millstones. No. 16,615, Patented Feb. l0, 1857.

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UNITED STATES PATENT OFFICE.

BENJ. D. SANDERS, OF HOLLIDAYS COVE, VIRGINIA.

INSTRUMENT FOR FACILITATING THE FACING OF MIL-LSTONES.

Specification of Letters Patent No. 16,615, dated February 10, 1857.

To all whom it may concern:

Be it known that I, BENJAMIN D. SAN- DERS, of Hollidays Cove, county of Brooke, and State of Virginia, have invented certain new and useful Improvements in Instruments for Facilitating the Facing of Millstones, of which the following is a full, clear, and exact description, reference being had to the accompanying drawing, which forms part of this specification, and in which- Figure 1 represents a side elevation of the instrument as applied to a mill bed-stone; Fig. 2, a plan of the same under a different application as regards the position of the instrument to the stone; and Fig. 3 represents a vertical section of the stone when worn concave, in illustration of the adaptability of the instrument as explained in after description.

In mills employing a bed-stone and a runner, it is necessary, to secure equal grinding and a proper operation of the stones, that, whether plane or whatever the dress, the faces of the stones should be kept true. This however is an impossibility for any great length of time, even with the best of stones, and the wear upon the faces of the stones is of necessity unequal, which will be readily understood when we consider the varying hardness of the stone over its face, the unequal feed or distribution of the substance to be ground, the varying resist ance which the substance being round presents at difierent points on the aces of the stones, and the varying velocities of those points in the traverse of the runner, and so forth. To correct then the inequalities of wear which thus take place is a frequent and most troublesome duty, and a most nice and difiicult one with the means at present employed for detecting unevenness in the face of the stone so that the operator may by chisel chip off the prominent or protruding portions to reduce the stone again to its proper level. The ordinary device employed for this purpose is the red staff which may be described as a long straight edge or straight strip of wood with red paint applied to the trying edge of it that is laid across the face of the stone in various directions crossing each other and wherever the paint touches and marks is afterward chipped or reduced till, by repeated trying, the staff, by marking across the entire face of the stone in various directions, in-

dicates that the stone is level, though this perfect result is seldom or never attained. Theoretically, this straight edge contrivance appears a perfect detector of inequalities for the purpose, but practically it is far from being so, for, in the first place, it is impossible to make a perfect straight edge and still less feasible to retain such an edge in a device which is required to be used from time to time; also when the stone has worn generally convex or concave (as illustrated in Fig. 3 of the drawing) such a device, it will be self evident, is altogether inapplicable; and when the surface is one that will admit of a straight edge being ap plied across it, the red staff deceives the operator as in applying it across the stone in one direction it marks at various points, which points may or may not be touched again, for there is no means of telling a new from an old mark of the same color, as he applies the staff or runs it across the stone in directions crossing the previous ones, or a raised point in the stone and an uneven pressure of the hands on the staff in running the staff across the stone may occasion the staff to tip and mark the stone where no mark should be made, and there can be no certainty as to the parts requiring reduction; while, the face of the stone, when afterward reduced, may form an incline to the vertical axis of the stone, which, when the two stones come together, is as bad as unevenness of surface.

My improvement obviates these defects and enables a true surface in such work to be produced with certainty as will appear from the following description of the instrument forming my improvement, and which may be used either separately or in connection with the red staff to detect inequalities or unevenness of surface in the stone. To a certain extent it resembles the beam compass but differs from that device in several important respects.

Referring to the drawing: On a base or stand (A) I erect a true spindle (a) that serves to guide and hold steady, for traverse around the spindle, a box (B), which is nicely bored to fit over the spindle and that has a set screw (5) inserted through its top in line with the axis of the spindle and projecting down'into the bore (0) of the box and said bore made of such length that the point of the screw serves as a fine conical or other shaped bearing on the top of the spindle to support or carry the box, admit of the easy swing or rotation of the box, and, by turning the screw to the right hand or to the left, also serves to raise or lower the box for a purpose that will be afterward explained.

The box (B) has branching out from it a beam (C). This beam is represented as jointed, for up and down play or adjustment, to the box, by a pin (cl) passing through any one of a series of holes in the box and through a hole in the back end of the beam, said joint being made a tightening one by a butt-on (e) screwing on to the end of the joint pin, or in any other way. A longitudinal slot (f) of any suitable length is made in the beam from its front end backward, which slotted portion of the beam serves to carry, and to have adjusted along it, a slotted cross arm or stick (D) that is secured to the beam (C) by a tightening button (g) fitting on the end of a screw which passes through the slots (f and h) of the beam and cross stick, by which means the cross stick may be adjusted high;

or low, backward or forward along the beam or at any desired angle to the beam.

other suitable and preferably elastic pointer over a plane or surface it will indicate by sound its contact with any irregular raised point or portion in said plane or surface without disturbing the adjustment of the swinging beam or cross arm which carries it.

The base or stand (A) that carries the whole I make adjustable at each of its corners by making slits near the bottom and parallel to the base or thereabout, and inserting in said slits (is) thin pieces of metal (Z) against which the points of screws passing down through the stand are made to butt, so that by turning any one or more of. the screws, its or their respective corners may be sprung and the stand at said corner or corners raised or lowered as desired.

To illustrate the utility and action of this instrument, suppose it applied to a mill bed-stone that is designed to be fiat on its face, (as represented in Figs. 1 and 2 of the drawing) but which surface has worn outof truth or level. Firstly, say, apply the red stafi' in the ordinary manner to the stone and use the instrument to detect the imperfect notations of the staff. Lay on the bed stone, close up to the spindle, a block and upon this block place a board (F) extending over the top of the spindle, upon which board, over the center of the stone or thereabout, seat the instrument by its stand (A) so that the spindle (a) of the instrument will be over, say, the center of the mill stone spindle. Then adjust the beam and cross arm by the means already This cross arm (D) carries at, say, its lower end, and pro ectlng therethrough, a quill or described for that purpose so as to bring the point of the quill nearly down to the face of the stone and so that in the sweep of the beam around the spindle (a) of the instrument the quill will be close to the outer diameter of the stone, more or less: then swing the beam over the stone and with it the quill from a point on the one side of the stone to a point opposite it on the other side and note the difference in height of the quills point at these two places and intermediate thereof in the traverse of the quill, and adjust the base of the instrument by the screws: (m) at the corners of the stand till the quill indicates, by its same ness of height from the face of the stone at the several places named, that the spindle (a) of the instrument is at right angles to the general plane or level of the stone and in axial line or parallel to the spindle of the stone. Thus set, turn the set screw (1)) so as to lower gently and with precision the beam, cross arm and quill till the latter touches or nearly so the face of the stone and swing the beam slowly around, noting the points which the quill scrapes or bears with greatest force on. Proceed in this manner, by making the necessary adjustment of the cross arm (D) along the beam and adjusting by the supporting screw (7)) the height of the quill from the face of or its contact with the stone, to describe a number of concentric circles, as represented in Fig. 2, noting in each circle described the raised points which the quill in scraping over will denote. These raised points or inequalities of level in the several circles may be afterward chipped or reduced.

In cases of general convexity or concavity of surface (as in Fig. 3) not admitting of the previous application of the red staff, or of similar partial wear or shape admitting of the partial application of the red staff, and even in all cases, if desired, the butt end (at) of the cross arm (D) may be turned downward and be painted so as to mark the stone at the raised places, by swinging around the beam (C) over the stone, previously to using the quill which latter, requiring no pressure to be exerted downwardly on it as the butt end in order to mark does and that in swaying down the beam unequally produces imperfect notations as does the red staff, may be used as an after or finishing detector to note inequalities not marked or improperly marked and to indicate with certainty how the stone should be dressed to be true, for there are instances where the stone might be redded all over by the red staff and still not be true. But as yet only one application of the instrument to the stone has been described.

To detect convexity or concavity and irregularity generally in the surface of the stone, place the instrument on one side of the stone or oil the stone near to it, as shown in Fig. 2, and having adjusted the instrument to its proper height and relative position to the general level of the stone, sweep the cross arm (D), first, say, the painted butt end (00) and then the quill across the center (more or less) of the stone in lines crossing each other, as also represented in Fig. 2, noting well the quills points of con tact or hard contact with the stone.

To keep the instrument steady when set and while setting and operating it, a weight (G) may be placed upon the stand (A), and this mode of holding it makes it convenient to move aboutto vary its courses that may be otherwise than those described according to the character of the work or will of the operator.

The flexible pointer prevents undue disturbance of the beam and cross arm, on the pointer in its swing meeting a raised surface or point, while it indicates by its sound the contact; and the universal adjustability of the whole instrument, including that of its base to bring the spindle of the instrument into right angles with the general level or surface of the work; also the raising and lowering of the whole swinging portions by the supporting set screw to suit requirements, without disturbing said swinging portions or stand proper, all combine to make the instrument perfect for the purpose I have described it, insuring correctness and applicable where the straight edge cannot well be applied, and possessing other advantages which it is not necessary here to name. By it all inequalities or unevenness of surface may be detected and a mill stone be afterward redressed true.

I do not claim any of the parts described, used separately, but

\Vhat I do claim, as an improvement in instruments for facilitating the facing of millstones, is:

The instrument above described, consisting of the slotted beam (C), cross arm (D), elastic pointer box (B) carrying the adjusting screw (5), spindle (a), and adjustable base or stand A), or the equivalents of these devices, constructed and arranged in relation to each other for joint operation substantially in the manner and for the purposes set forth.

In testimony whereof, I have hereunto subscribed my name.

B. D. SANDERS.

Witnesses A. DUVALL, JOHN S. HoLLINcsHEAD. 

